Potential divider problem

attached is an image containing 2 potential divider setups.
i have a few questions about them, and any help would be appreciated!

a) for the first setup, A, how could the 10k pot be split into 2 resistors to give a Vout of 3v? i am confused by the +-15v source. can i treat this as if the +15v is 30v and the -15 is 0v? making the 2 resistors 9k and 1k? if not, how else is it done; i can find absolutely no examples of potential diviers which aren't grounded?

b) how do i calculate the thevenin source impedance of the potentiometer set to give 3v? im familliar with thevenin's theorem but dont fully understand the question. as far as i understand, thevenins thereom is used to reduc circuits down to just a voltage source, a resistor and a load; here i'm unsure how this would be done.

c)finally, how do i calculate Vout for the setup B when the effective impedance of the multi meter measuring Vout is reduced to 3.3K? my initial thought was a simple voltage division equation but this came unstuck when i realised that R1 = 0, therefore that doesnt work. im out of ideas after that!

i9 realise ive been being a fool.
think the output voltage can vary anywhere between -15V and +15V; a range of 30V.
An output of +3V is therefore 18V above the lower -15 level and 12V below the +15 level. In other words, the potential divider must divide the 30V total in the ratio 12/18. The resistance ratio must be the same; 4 ohm and 6 ohm